This invention relates to electrostatographic copiers and printers, and more particularly to a high quality and heat efficient method and apparatus therein for fixing images on a suitable receiver or copy sheet of paper without subjecting the receiver or copy sheet to high fusing temperatures and heat. The method and apparatus of the present invention thereby substantially prevent the occurrence of heat-related fusing and fixing defects such as curling, distortion, blistering and even charring of such a receiver or copy sheet.
Processes in electrostatographic copiers and printers for creating electrostatic latent images on an image-bearing member, developing such images with loose particles of toner, and then transferring the loose toner developed images to a suitable receiver or copy sheet of paper, are well known. In order to form a permanent copy of such images on the receiver or copy sheet, it is also well known to use heat for fusing and and/or pressure for fixing such loose particles of toner to the receiver or copy sheet. For such fusing and fixing, the loose toner particle images conventionally are transferred unfused to a heat absorbing receiver or copy sheet, and there fused by applying heat and pressure to the receiver or copy sheet.
In copiers or printers with roller fusing and fixing apparatus, the heat for fusing is supplied and applied by means of a heated roller, and in those with radiant fusing apparatus, the heat is supplied, for example, by an infrared heat source. In such conventional fusing and fixing apparatus, a substantial and extra amount of the heat generated by the heat source is unfortunately absorbed by the receiver or copy sheet. As a result, a lot more heat than is necessary to fuse such toner particles is detrimentally generated, and wasted by the apparatus. Additionally, because it takes time to produce such extra heat, conventional apparatus therefore take more time, than would otherwise be necessary, to heat fuse the loose toner images on such receiver or copy sheet.
Consequently, the quality of the fused images often is adversely affected, and the receiver or copy sheet, which is subjected to and adsorbs such a substantial amount of heat at high fusing temperatures, is likely to suffer from heat-related fusing and fixing defects such as curling, distortion, blistering and charring of such receiver or copy sheet.